Meaning:
If you want to keep in contact with someone you just met, ask this question to find out their phone number.
Examples:
- What is your phone number, Miss Nirali?
- I'll give you a call when I finish. What is your phone number?
- My family only has one phone. - I see. What is your phone number?
- What is your phone number? - I'm not going to give it to you.